On 2022-10-03 13:08:49 [-0400], Eric Chanudet wrote: > PREEMPT_RT forces qcom-ipcc's handler to be threaded with interrupts > enabled, which triggers a warning in __handle_irq_event_percpu(): > irq 173 handler irq_default_primary_handler+0x0/0x10 enabled interrupts > WARNING: CPU: 0 PID: 77 at kernel/irq/handle.c:161 __handle_irq_event_percpu+0x4c4/0x4d0 > > Mark it IRQF_NO_THREAD to avoid running the handler in a threaded > context with threadirqs or PREEMPT_RT enabled. The important bit of information is that this is a IRQ-multiplexer and such it must not be threaded. Otherwise its child-interrupts would be invoked from the thread handler which is not desired. This is noticed by PREEMPT_RT but also on a non-PREEMPT_RT kernel where `threadirqs' has been used. Side note: Using request_irq() has the side effect that this interrupt pops-up in /proc/interrupts and the "child-interrupt", too. So you account two interrupts while "one" on the HW side occurred. Maybe irq_set_chained_handler_and_data() would be better use. Either way, this addresses the problem, Acked-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > Signed-off-by: Eric Chanudet <echanude@xxxxxxxxxx> Sebastian
